[mirror_ubuntu-bionic-kernel.git] / drivers / cpuidle / driver.c

/*
 * driver.c - driver support
 *
 * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *               Shaohua Li <shaohua.li@intel.com>
 *               Adam Belay <abelay@novell.com>
 *
 * This code is licenced under the GPL.
 */

#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/cpuidle.h>

#include "cpuidle.h"

DEFINE_SPINLOCK(cpuidle_driver_lock);

static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu);
static struct cpuidle_driver * __cpuidle_get_cpu_driver(int cpu);

static void __cpuidle_driver_init(struct cpuidle_driver *drv)
{
	drv->refcnt = 0;
}

static int __cpuidle_register_driver(struct cpuidle_driver *drv, int cpu)
{
	if (!drv || !drv->state_count)
		return -EINVAL;

	if (cpuidle_disabled())
		return -ENODEV;

	if (__cpuidle_get_cpu_driver(cpu))
		return -EBUSY;

	__cpuidle_driver_init(drv);

	__cpuidle_set_cpu_driver(drv, cpu);

	return 0;
}

static void __cpuidle_unregister_driver(struct cpuidle_driver *drv, int cpu)
{
	if (drv != __cpuidle_get_cpu_driver(cpu))
		return;

	if (!WARN_ON(drv->refcnt > 0))
		__cpuidle_set_cpu_driver(NULL, cpu);
}

#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS

static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers);

static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu)
{
	per_cpu(cpuidle_drivers, cpu) = drv;
}

static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
{
	return per_cpu(cpuidle_drivers, cpu);
}

static void __cpuidle_unregister_all_cpu_driver(struct cpuidle_driver *drv)
{
	int cpu;
	for_each_present_cpu(cpu)
		__cpuidle_unregister_driver(drv, cpu);
}

static int __cpuidle_register_all_cpu_driver(struct cpuidle_driver *drv)
{
	int ret = 0;
	int i, cpu;

	for_each_present_cpu(cpu) {
		ret = __cpuidle_register_driver(drv, cpu);
		if (ret)
			break;
	}

	if (ret)
		for_each_present_cpu(i) {
			if (i == cpu)
				break;
			__cpuidle_unregister_driver(drv, i);
		}


	return ret;
}

int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu)
{
	int ret;

	spin_lock(&cpuidle_driver_lock);
	ret = __cpuidle_register_driver(drv, cpu);
	spin_unlock(&cpuidle_driver_lock);

	return ret;
}

void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu)
{
	spin_lock(&cpuidle_driver_lock);
	__cpuidle_unregister_driver(drv, cpu);
	spin_unlock(&cpuidle_driver_lock);
}

/**
 * cpuidle_register_driver - registers a driver
 * @drv: the driver
 */
int cpuidle_register_driver(struct cpuidle_driver *drv)
{
	int ret;

	spin_lock(&cpuidle_driver_lock);
	ret = __cpuidle_register_all_cpu_driver(drv);
	spin_unlock(&cpuidle_driver_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(cpuidle_register_driver);

/**
 * cpuidle_unregister_driver - unregisters a driver
 * @drv: the driver
 */
void cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
	spin_lock(&cpuidle_driver_lock);
	__cpuidle_unregister_all_cpu_driver(drv);
	spin_unlock(&cpuidle_driver_lock);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);

#else

static struct cpuidle_driver *cpuidle_curr_driver;

static inline void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu)
{
	cpuidle_curr_driver = drv;
}

static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
{
	return cpuidle_curr_driver;
}

/**
 * cpuidle_register_driver - registers a driver
 * @drv: the driver
 */
int cpuidle_register_driver(struct cpuidle_driver *drv)
{
	int ret, cpu;

	cpu = get_cpu();
	spin_lock(&cpuidle_driver_lock);
	ret = __cpuidle_register_driver(drv, cpu);
	spin_unlock(&cpuidle_driver_lock);
	put_cpu();

	return ret;
}
EXPORT_SYMBOL_GPL(cpuidle_register_driver);

/**
 * cpuidle_unregister_driver - unregisters a driver
 * @drv: the driver
 */
void cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
	int cpu;

	cpu = get_cpu();
	spin_lock(&cpuidle_driver_lock);
	__cpuidle_unregister_driver(drv, cpu);
	spin_unlock(&cpuidle_driver_lock);
	put_cpu();
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
#endif

/**
 * cpuidle_get_driver - return the current driver
 */
struct cpuidle_driver *cpuidle_get_driver(void)
{
	struct cpuidle_driver *drv;
	int cpu;

	cpu = get_cpu();
	drv = __cpuidle_get_cpu_driver(cpu);
	put_cpu();

	return drv;
}
EXPORT_SYMBOL_GPL(cpuidle_get_driver);

/**
 * cpuidle_get_cpu_driver - return the driver tied with a cpu
 */
struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
{
	if (!dev)
		return NULL;

	return __cpuidle_get_cpu_driver(dev->cpu);
}
EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver);

struct cpuidle_driver *cpuidle_driver_ref(void)
{
	struct cpuidle_driver *drv;

	spin_lock(&cpuidle_driver_lock);

	drv = cpuidle_get_driver();
	drv->refcnt++;

	spin_unlock(&cpuidle_driver_lock);
	return drv;
}

void cpuidle_driver_unref(void)
{
	struct cpuidle_driver *drv = cpuidle_get_driver();

	spin_lock(&cpuidle_driver_lock);

	if (drv && !WARN_ON(drv->refcnt <= 0))
		drv->refcnt--;

	spin_unlock(&cpuidle_driver_lock);
}
Commit	Line	Data
4f86d3a8 LB	1	/*
	2	* driver.c - driver support
	3	*
	4	* (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
	5	* Shaohua Li <shaohua.li@intel.com>
	6	* Adam Belay <abelay@novell.com>
	7	*
	8	* This code is licenced under the GPL.
	9	*/
	10
	11	#include <linux/mutex.h>
	12	#include <linux/module.h>
	13	#include <linux/cpuidle.h>
	14
	15	#include "cpuidle.h"
	16
4f86d3a8 LB	17	DEFINE_SPINLOCK(cpuidle_driver_lock);
4f86d3a8 LB	18
bf4d1b5d DL	19	static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu);
	20	static struct cpuidle_driver * __cpuidle_get_cpu_driver(int cpu);
	21
13dd52f1 DL	22	static void __cpuidle_driver_init(struct cpuidle_driver *drv)
	23	{
	24	drv->refcnt = 0;
13dd52f1 DL	25	}
13dd52f1 DL	26
bf4d1b5d	27	static int __cpuidle_register_driver(struct cpuidle_driver *drv, int cpu)
4f86d3a8	28	{
fc850f39	29	if (!drv \|\| !drv->state_count)
4f86d3a8 LB	30	return -EINVAL;
4f86d3a8 LB	31
62027aea LB	32	if (cpuidle_disabled())
	33	return -ENODEV;
	34
bf4d1b5d	35	if (__cpuidle_get_cpu_driver(cpu))
4f86d3a8	36	return -EBUSY;
ed953472	37
13dd52f1	38	__cpuidle_driver_init(drv);
ed953472	39
bf4d1b5d	40	__cpuidle_set_cpu_driver(drv, cpu);
42f67f2a	41
13dd52f1 DL	42	return 0;
	43	}
	44
bf4d1b5d	45	static void __cpuidle_unregister_driver(struct cpuidle_driver *drv, int cpu)
13dd52f1	46	{
bf4d1b5d	47	if (drv != __cpuidle_get_cpu_driver(cpu))
13dd52f1 DL	48	return;
	49
	50	if (!WARN_ON(drv->refcnt > 0))
bf4d1b5d DL	51	__cpuidle_set_cpu_driver(NULL, cpu);
	52	}
	53
	54	#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
	55
	56	static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers);
	57
	58	static void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu)
	59	{
	60	per_cpu(cpuidle_drivers, cpu) = drv;
	61	}
	62
	63	static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
	64	{
	65	return per_cpu(cpuidle_drivers, cpu);
	66	}
	67
	68	static void __cpuidle_unregister_all_cpu_driver(struct cpuidle_driver *drv)
	69	{
	70	int cpu;
	71	for_each_present_cpu(cpu)
	72	__cpuidle_unregister_driver(drv, cpu);
	73	}
	74
	75	static int __cpuidle_register_all_cpu_driver(struct cpuidle_driver *drv)
	76	{
	77	int ret = 0;
	78	int i, cpu;
	79
	80	for_each_present_cpu(cpu) {
	81	ret = __cpuidle_register_driver(drv, cpu);
	82	if (ret)
	83	break;
	84	}
	85
	86	if (ret)
	87	for_each_present_cpu(i) {
	88	if (i == cpu)
	89	break;
	90	__cpuidle_unregister_driver(drv, i);
	91	}
	92
	93
	94	return ret;
	95	}
	96
	97	int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu)
	98	{
	99	int ret;
	100
	101	spin_lock(&cpuidle_driver_lock);
	102	ret = __cpuidle_register_driver(drv, cpu);
	103	spin_unlock(&cpuidle_driver_lock);
	104
	105	return ret;
	106	}
	107
	108	void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu)
	109	{
	110	spin_lock(&cpuidle_driver_lock);
	111	__cpuidle_unregister_driver(drv, cpu);
	112	spin_unlock(&cpuidle_driver_lock);
13dd52f1	113	}
ed953472	114
13dd52f1 DL	115	/**
	116	* cpuidle_register_driver - registers a driver
	117	* @drv: the driver
	118	*/
	119	int cpuidle_register_driver(struct cpuidle_driver *drv)
	120	{
	121	int ret;
	122
	123	spin_lock(&cpuidle_driver_lock);
bf4d1b5d	124	ret = __cpuidle_register_all_cpu_driver(drv);
4f86d3a8 LB	125	spin_unlock(&cpuidle_driver_lock);
4f86d3a8 LB	126
13dd52f1	127	return ret;
4f86d3a8	128	}
4f86d3a8 LB	129	EXPORT_SYMBOL_GPL(cpuidle_register_driver);
4f86d3a8 LB	130
752138df	131	/**
bf4d1b5d DL	132	* cpuidle_unregister_driver - unregisters a driver
bf4d1b5d DL	133	* @drv: the driver
752138df	134	*/
bf4d1b5d DL	135	void cpuidle_unregister_driver(struct cpuidle_driver *drv)
	136	{
	137	spin_lock(&cpuidle_driver_lock);
	138	__cpuidle_unregister_all_cpu_driver(drv);
	139	spin_unlock(&cpuidle_driver_lock);
	140	}
	141	EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
	142
	143	#else
	144
	145	static struct cpuidle_driver *cpuidle_curr_driver;
	146
	147	static inline void __cpuidle_set_cpu_driver(struct cpuidle_driver *drv, int cpu)
	148	{
	149	cpuidle_curr_driver = drv;
	150	}
	151
	152	static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
752138df LB	153	{
	154	return cpuidle_curr_driver;
	155	}
bf4d1b5d DL	156
	157	/**
	158	* cpuidle_register_driver - registers a driver
	159	* @drv: the driver
	160	*/
	161	int cpuidle_register_driver(struct cpuidle_driver *drv)
	162	{
	163	int ret, cpu;
	164
	165	cpu = get_cpu();
	166	spin_lock(&cpuidle_driver_lock);
	167	ret = __cpuidle_register_driver(drv, cpu);
	168	spin_unlock(&cpuidle_driver_lock);
	169	put_cpu();
	170
	171	return ret;
	172	}
	173	EXPORT_SYMBOL_GPL(cpuidle_register_driver);
752138df	174
4f86d3a8 LB	175	/**
	176	* cpuidle_unregister_driver - unregisters a driver
	177	* @drv: the driver
	178	*/
	179	void cpuidle_unregister_driver(struct cpuidle_driver *drv)
	180	{
bf4d1b5d DL	181	int cpu;
	182
	183	cpu = get_cpu();
4f86d3a8	184	spin_lock(&cpuidle_driver_lock);
bf4d1b5d	185	__cpuidle_unregister_driver(drv, cpu);
4f86d3a8	186	spin_unlock(&cpuidle_driver_lock);
bf4d1b5d	187	put_cpu();
4f86d3a8	188	}
4f86d3a8	189	EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
bf4d1b5d DL	190	#endif
	191
	192	/**
	193	* cpuidle_get_driver - return the current driver
	194	*/
	195	struct cpuidle_driver *cpuidle_get_driver(void)
	196	{
	197	struct cpuidle_driver *drv;
	198	int cpu;
	199
	200	cpu = get_cpu();
	201	drv = __cpuidle_get_cpu_driver(cpu);
	202	put_cpu();
	203
	204	return drv;
	205	}
	206	EXPORT_SYMBOL_GPL(cpuidle_get_driver);
	207
	208	/**
	209	* cpuidle_get_cpu_driver - return the driver tied with a cpu
	210	*/
	211	struct cpuidle_driver cpuidle_get_cpu_driver(struct cpuidle_device dev)
	212	{
bf4d1b5d DL	213	if (!dev)
	214	return NULL;
	215
ac34d7c8	216	return __cpuidle_get_cpu_driver(dev->cpu);
bf4d1b5d DL	217	}
bf4d1b5d DL	218	EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver);
6e797a07 RW	219
	220	struct cpuidle_driver *cpuidle_driver_ref(void)
	221	{
	222	struct cpuidle_driver *drv;
	223
	224	spin_lock(&cpuidle_driver_lock);
	225
13dd52f1	226	drv = cpuidle_get_driver();
42f67f2a	227	drv->refcnt++;
6e797a07 RW	228
	229	spin_unlock(&cpuidle_driver_lock);
	230	return drv;
	231	}
	232
	233	void cpuidle_driver_unref(void)
	234	{
13dd52f1	235	struct cpuidle_driver *drv = cpuidle_get_driver();
42f67f2a	236
6e797a07 RW	237	spin_lock(&cpuidle_driver_lock);
6e797a07 RW	238
42f67f2a DL	239	if (drv && !WARN_ON(drv->refcnt <= 0))
42f67f2a DL	240	drv->refcnt--;
6e797a07 RW	241
	242	spin_unlock(&cpuidle_driver_lock);
	243	}